Massage devices are commonly used equipments for relaxing muscles of users. These massage devices contain complex transmission elements therein for realizing comfortable muscle-relaxing effects. Generally, a set of gears and a pair of rack-type rails are employed to move certain kneading structure of a massage device back and forth.
The set of gears can be driven by a motor mounted in the massage device so as to move the kneading structure along the pair of rails. When no power is input to the motor, the gears are free from drive of the motor and thus can move relative to the rails when sudden external forces are applied to the massage device.
Undesirable movement of the gears due to sudden external forces most often occurs during transportation of the massage device e.g. from a manufacture place to a sale place, as during transportation, variable forces are applied to the massage device and thus make the gears move back and forth with respect to the rails. Frequent and sudden movement of the gears with respect to the rails results in worn-out and even broken damage of the gears/rails. Consequently, the gears/rails will be out of use and the entire massage device will lose its function.
Hence, it is desired to provide a massage device to solve the above-mentioned problems.